Polymerization Time-Optimized Covalent Organic Framework for Ultrasensitive Ethylene Glycol Sensing

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Ethylene glycol (C2H6O2) is a common but toxic chemical necessitating efficient, low-temperature detection methods.
• Existing high-temperature sensors are energy-intensive and less suitable for certain applications.
• Covalent organic frameworks (COFs) offer tunable properties for advanced sensing applications.

Purpose of the Study:

• To synthesize and characterize an imine COF (COF-TPC) for ethylene glycol detection at room temperature.
• To investigate the structure-property relationship of COF-TPC sensors by varying synthesis time.
• To evaluate the sensor's performance, selectivity, stability, and moisture resistance for ethylene glycol detection.

Main Methods:

• Room-temperature synthesis of COF-TPC using specific ligands (Tp and Pa-Cl) and acetic acid catalyst.
• Fabrication of four distinct sensors (COF-T-30, COF-T-40, COF-T-50, COF-T-60) by controlling Schiff base reaction time.
• Gas sensing performance evaluation, including response, selectivity across 13 gases, repeatability, and moisture resistance tests.
• Density Functional Theory (DFT) calculations to elucidate adsorption mechanisms and selectivity origins.

Main Results:

• The COF-T-50 sensor demonstrated a high response (6107%) to 500 ppm ethylene glycol.
• COF-T-50 exhibited superior performance compared to other synthesized sensors.
• Exceptional selectivity towards ethylene glycol among 13 tested gases was observed, alongside excellent repeatability and moisture resistance.

Conclusions:

• Room-temperature synthesized COF-TPC, particularly COF-T-50, provides a highly effective platform for ethylene glycol detection.
• The developed sensor offers an energy-efficient, stable, and selective alternative to traditional methods.
• This research expands the application scope of COFs in rapid and reliable gas sensing.